These functions are specific to Cygwin itself, and probably won't be found anywhere else.
extern "C" int
cygwin_attach_handle_to_fd(char *name, int fd, HANDLE handle, int bin, int access);This function can be used to turn a Win32 "handle" into a posix-style file handle. fd may be -1 to make cygwin allocate a handle; the actual handle is returned in all cases.